Data bearing devices comprising a covertly coded data embedded pattern are widely used as in authentication, identification, tracking, telecommunications, verification, and other applications. For example, information bearing devices such as digital watermarks are frequently incorporated in documents such as identification documents, certificates, authorization permits; articles such as product tags and labels and valuable articles such as credit cards, currency notes and the like. In many applications, the data embedded pattern is usually formed as a background image pattern, as a foreground image pattern or as a mixture of both. Data bearing devices comprising overtly coded data units are also widely used as information sources. Barcodes and QR (RTM) codes are common example of this type of data devices.
A composite information bearing device comprising a first data bearing device formed of overtly coded data units and a second bearing device formed of a covertly coded data embedded pattern which at least partially overlap to form a overlapping data bearing portion is useful. Overlapping of data bearing portions results in an increase in data density as well as an increase in difficulty of copying and/or data recovery.